ElasticHosts is offering a next-generation cloud service that it claims could halve the cost of computing for Linux IaaS (Infrastructure as a Service) customers. What's more, the change is relatively simple, and could well become widespread, thanks to Linux LXC containers and the Docker automated deployment system.

Richard Davies Photo: ElasticHosts

ElasticHosts' chief executive Richard Davies explained in a telephone interview that most IaaS customers pay for virtual machines (VMs) on contracts that run for up to two years. Because usage isn't constant, the VM capacity is mostly underused, though at peak times, it may not be big enough — see graph below. The ElasticHosts alternative is to use containers, where a single VM can run containers for many different customers. The container can easily be scaled up and down, up to predetermined maximum such as 64GB. ElasticHosts charges only for the capacity used.

Users are familiar with paying for the use of bandwidth. With Elastic Containers, they can be billed separately for on-demand memory, processor and disk use as well.

Based on its extensive experience in offering cloud services, ElasticHosts claims that "Organisations deploying web applications can typically save around 50 percent through using auto-scaling containers, as opposed to fixed-size virtual machines." Companies that use cloud services for disaster recovery — where provisioning is high but usage is typically very low — could save "80 percent or more", it says.

ElasticHosts used industry figures to estimate the total cost savings. Gartner has put the global IaaS market at £5.4 billion ($9.2bn), and ElasticHosts calculates that Linux accounts for £2.05bn ($3.5bn) of that. Assuming 50 percent utilisation for VMs, containerization would save at least £1bn ($1.7bn).

The ElasticHosts service is based on containerization features added to the Linux kernel. These features are also used to support Linux LXC containers, where "The goal of LXC is to create an environment as close as possible as a standard Linux installation but without the need for a separate kernel". Davies says Elastic Containers are not actually based on LXC, but "the technology is very LXC-like."

My assumption is that LXC support in numerous Linux distros plus the growing popularity of Docker means that containerization will become widespread. LXC 1.0, released in February, does not require special patches to be applied to the Linux kernel, and allows for "unprivileged containers" that cannot access hardware directly. This enables customers to be securely isolated from one another.

Davies says "each [ElasticHosts] customer runs on its own isolated partitions. When users log on, they can only see their own processes, and they can only install software in their own containers."

Davies adds that there are also benefits for the cloud service provider: "you don't have the virtualization overhead, so the result is more efficient."

ElasticHosts also offers traditional virtual machines and managed cloud servers. The UK-based company says it has nine data centres in Europe, North America and Asia, and customers in more than 60 countries worldwide.

ElasticHosts argues that, with fixed-size VMs, users are often paying for capacity that they are not using much of the time. With auto-scaling containers, they only pay for what they use.